Browse Our Dictionary Alphabetically
Section H


A kind of back clip harness, particularly used for smaller dogs, comprised of two loops that fit around the top of the chest and the belly, joined together with a strip that runs along the spine.


“Getting used to” something.  After consistent exposure to a stimulus at a level that does not cause it concern, a dog starts to see that stimulus as neutral and no longer responds to its presence in the environment.

For example, a dog might initially react with concern to a Christmas tree that has been left on the side of the road, and thoroughly investigate it.  After a few days of walking the same route, the tree is still there, but the dog no longer notices it.

Hard Mouth

When a dog is stressed, he can sometimes take treats more forcefully than usual, causing some discomfort to the handler.  Teeth can often be felt against the skin, but there is no aggression, just a lack of adequate control due to stress.

In a counter-conditioning setup, a hard mouth is often considered to be evidence that the dog is too close to the trigger, and should move far enough away that he can take treats with a soft mouth.

Head Halter

A training tool for dogs.  The halter fits over the dog’s muzzle and neck and attaches to a leash.  When the dog tries to pull on the leash, the owner can guide the dog’s head in another direction.  Because the leash is attached to the head rather than the neck or the body, the owner needs to use much less force to make the dog turn in the desired direction.


Part of obedience. A dog walks close to the handler’s left side, following her movements and sitting as a default behavior when the handler stops.

Heeling is a foundation for many sports, including Rally and Heelwork to Music (Dog Dancing).

Loose leash walking is different from heelwork in the strictness of its criteria – all that is required for loose leash walking is that the dog does not pull on the leash, he does not need to be in a specific position relative to the handler.


A private laboratory, run by Dr Jean Dodds, which offers a suite of unique measures of certain blood tests, especially thyroid levels.

Hind/Rear End Awareness

In sport and working dogs, it is considered to be important that they are trained to be aware of each of their limbs independently, and to be more conscious of where their body is in relation to their environment.  Rear end awareness exercises are designed to help with this.  Examples include:
  • Backing up
  • Backing onto a platform or wall
  • Targeting a paw pod or object with each foot
  • Balancing exercises
These exercise can also be used as part of rehabilitation and conditioning, as they improve balance, co-ordination and strength.

Homeopathic Remedies

Medications prepared according to homeopathic principles.  The principle of homeopathy was invented by Samuel Christian Friedrich Hahnemann in the 19th Century. It is based on the idea that “like cures like” and that the more an active ingredient is diluted, the more potent the preparation will become.

Homeopathic preparations have been systematically shown not to have any effect on the problems they are designed to treat, however this is disputed.

Not to be confused with natural remedies or nutraceuticals.

Hot Spot

A lesion on a dog’s skin, which comes up as the result of an allergen such as a flea bite or a food allergy. Also called acute moist or pyotramatic dermatitis. Hot spots are warm to the touch.


A state of constant, heightened awareness of, and sensitivity to, changes in the environment.  For example, a dog that orients towards every noise he hears so that he never stops moving or can settle is considered to be hypervigilant.

Hypervigilance can be caused by arousal or anxiety.  It can be dependent on context for some dogs, and a constant problem for others.


A disorder of the endocrine system, which controls levels of hormones in the body. The thyroid gland does not produce enough hormone, which can lead to symptoms including aggression and anxiety. Hypothyroidism is diagnosed through a blood test and treatable with medication.